Apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcase signals and method for receiving broadcast signals

ABSTRACT

A method and an apparatus for transmitting broadcast signals thereof are disclosed. The method for transmitting broadcast signals includes processing input streams into BB frames in PLPs; encoding data of the PLPs; building at least one signal frame by mapping the encoded data of the PLPs; and modulating data in the built signal frame by OFDM method and transmitting the broadcast signals having the modulated data, wherein at least one of the BB frames includes a stuffing field and a first indicator describing whether the stuffing field is included in the BB frame.

Pursuant to 35 U.S.C. §119(e), this application also claims the benefitof U.S. Provisional Application Ser. No. 61/859,298, filed on Jul. 29,2013, the contents of which are hereby incorporated by reference intheir entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for transmitting broadcastsignals, an apparatus for receiving broadcast signals and methods fortransmitting and receiving broadcast signals.

2. Discussion of the Related Art

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

That is, a digital broadcast system can provide HD (high definition)images, multi-channel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an apparatus fortransmitting broadcast signals and an apparatus for receiving broadcastsignals for future broadcast services and methods for transmitting andreceiving broadcast signals for future broadcast services.

An object of the present invention devised to solve the problem lies onan apparatus and method for transmitting broadcast signals to multiplexdata of a broadcast transmission/reception system providing two or moredifferent broadcast services in a time domain and transmit themultiplexed data through the same RF signal bandwidth and an apparatusand method for receiving broadcast signals corresponding thereto.

Another object of the present invention devised to solve the problemlies on an apparatus for transmitting broadcast signals, an apparatusfor receiving broadcast signals and methods for transmitting andreceiving broadcast signals to classify data corresponding to servicesby components, transmit data corresponding to each component as a datapipe, receive and process the data

Another object of the present invention devised to solve the problemlies on an apparatus for transmitting broadcast signals, an apparatusfor receiving broadcast signals and methods for transmitting andreceiving broadcast signals to signal signaling information necessary toprovide broadcast signals.

The object of the present invention can be achieved by providing amethod of transmitting broadcast signals including processing inputstreams into BB (Base Band) frames in PLPs (Physical Layer Pipes);encoding data of the PLPs; building at least one signal frame by mappingthe encoded data of the PLPs; and modulating data in the built signalframe by OFDM (Orthogonal Frequency Division Multiplexing) method andtransmitting the broadcast signals having the modulated data, wherein atleast one of the BB frames includes a stuffing field and a firstindicator describing whether the stuffing field is included in the BBframe.

Preferably, the processing input streams further includes, generatingdata fields of the BB frames by using the input streams, and insertingBB frame headers to the BB frames.

Preferably, the BB frame further includes a second indicator indicatinglength of the stuffing field.

Preferably, the BB frame further includes a third indicator havinginformation about composition of the BB frame.

Preferably, the information in the third indicator indicates a type ofstuffing data in the stuffing field.

Preferably, the encoding data of the PLPs further includes, encoding theBB frames in the PLPs with LDPC (Low Density Parity Check) codes, bitinterleaving the LDPC encoded data in the PLPs, mapping the bitinterleaved data onto constellations, MIMO (Multi Input Multi Output)encoding the mapped data, and time interleaving the MIMO encoded data.

In another aspect of the present invention, provided herein is an methodof receiving broadcast signals including receiving the broadcast signalshaving at least one signal frame and demodulating data in the at leastone signal frame by OFDM (Orthogonal Frequency Division Multiplexing)method; parsing the at least one signal frame by demapping data of PLPs(Physical Layer Pipes); decoding the data of the PLPs; and processing BB(Base Band) frames in the PLPs to output streams, wherein at least oneof the BB frames includes a stuffing field and a first indicatordescribing whether the stuffing field is included in the BB frame.

Preferably, the processing BB frames in the PLPs further includes,removing BB frame headers from the BB frames, and generating outputstreams by using data fields of the BB frames.

Preferably, the BB frame further includes a second indicator indicatinglength of the stuffing field.

Preferably, the BB frame further includes a third indicator havinginformation about composition of the BB frame.

Preferably, the information in the third indicator indicates a type ofstuffing data in the stuffing field.

Preferably, the decoding the data of the PLPs further includes, timedeinterleaving the data of the PLPs, MIMO (Multi Input Multi Output)decoding the time deinterleaved data of the PLPs, demapping the MIMOdecoded data from constellations, bit deinterleaving the demapped data,and processing the bit deinterleaved data with LDPC (Low Density ParityCheck) codes to output BB frames.

In another aspect of the present invention, provided herein is anapparatus for transmitting broadcast signals including an inputprocessing module for processing input streams into BB (Base Band)frames in PLPs (Physical Layer Pipes); an encoding module for encodingdata of the PLPs; a frame building module for building at least onesignal frame by mapping the encoded data of the PLPs; and a modulatingmodule for modulating data in the built signal frame by OFDM (OrthogonalFrequency Division Multiplexing) method and transmitting the broadcastsignals having the modulated data, wherein at least one of the BB framesincludes a stuffing field and a first indicator describing whether thestuffing field is included in the BB frame.

Preferably, the input processing module further includes, a generatingblock for generating data fields of the BB frames by using the inputstreams, and a inserting block for inserting BB frame headers to the BBframes.

Preferably, the BB frame further includes a second indicator indicatinglength of the stuffing field.

Preferably, the BB frame further includes a third indicator havinginformation about composition of the BB frame.

Preferably, the information in the third indicator indicates a type ofstuffing data in the stuffing field.

Preferably, the encoding module further includes, a LDPC block forencoding the BB frames in the PLPs with LDPC (Low Density Parity Check)codes, a bit interleaving block for bit interleaving the LDPC encodeddata in the PLPs, a constellation mapping block for mapping the bitinterleaved data onto constellations, a MIMO (Multi Input Multi Output)block for MIMO encoding the mapped data, and a time interleaving blockfor time interleaving the MIMO encoded data.

In another aspect of the present invention, provided herein is anapparatus for receiving broadcast signals including a demodulatingmodule for receiving the broadcast signals having at least one signalframe and demodulating data in the at least one signal frame by OFDM(Orthogonal Frequency Division Multiplexing) method; a frame parsingmodule for parsing the at least one signal frame by demapping data ofPLPs (Physical Layer Pipes); a decoding module for decoding the data ofthe PLPs; and a output processing module for processing BB (Base Band)frames in the PLPs to output streams, wherein at least one of the BBframes includes a stuffing field and a first indicator describingwhether the stuffing field is included in the BB frame.

Preferably, the output processing module further includes, a removingblock for removing BB frame headers from the BB frames, and a generatingblock for generating output streams by using data fields of the BBframes.

Preferably, the BB frame further includes a second indicator indicatinglength of the stuffing field.

Preferably, the BB frame further includes a third indicator havinginformation about composition of the BB frame.

Preferably, the information in the third indicator indicates a type ofstuffing data in the stuffing field.

Preferably, the decoding module further includes, a time deinterleavingblock for time deinterleaving the data of the PLPs, a MIMO (Multi InputMulti Output) decoding block for MIMO decoding the time deinterleaveddata of the PLPs, a constellation demapping block for demapping the MIMOdecoded data from constellations, a bit deinterleaving block for bitdeinterleaving the demapped data, and a LDPC decoding block forprocessing the bit deinterleaved data with LDPC (Low Density ParityCheck) codes to output BB frames.

The present invention can process data according to servicecharacteristics to control QoS for each service or service component,thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same RF signalbandwidth.

The present invention can improve data transmission efficiency andincrease robustness of transmission/reception of broadcast signals usinga MIMO system.

According to the present invention, it is possible to provide broadcastsignal transmission and reception methods and apparatus capable ofreceiving digital broadcast signals without error even with mobilereception equipment or in an indoor environment

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

FIG. 2 illustrates an input formatting module according to an embodimentof the present invention.

FIG. 3 illustrates an input formatting module according to anotherembodiment of the present invention.

FIG. 4 illustrates an input formatting module according to anotherembodiment of the present invention.

FIG. 5 illustrates a coding & modulation module according to anembodiment of the present invention.

FIG. 6 illustrates a frame structure module according to an embodimentof the present invention.

FIG. 7 illustrates a waveform generation module according to anembodiment of the present invention.

FIG. 8 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

FIG. 9 illustrates a synchronization & demodulation module according toan embodiment of the present invention.

FIG. 10 illustrates a frame parsing module according to an embodiment ofthe present invention.

FIG. 11 illustrates a demapping & decoding module according to anembodiment of the present invention.

FIG. 12 illustrates an output processor according to an embodiment ofthe present invention.

FIG. 13 illustrates an output processor according to another embodimentof the present invention.

FIG. 14 illustrates a coding & modulation module according to anotherembodiment of the present invention.

FIG. 15 illustrates a demapping & decoding module according to anotherembodiment of the present invention.

FIG. 16 is a view illustrating a mode adaptation module according toanother embodiment of the present invention.

FIG. 17 is a view illustrating an output processor according to anotherembodiment of the present invention.

FIG. 18 is a view illustrating a BB frame generation procedure accordingto a related art.

FIG. 19 is a view illustrating a BB frame generation procedure accordingto another related art.

FIG. 20 is a view illustrating a BB frame generation procedure accordingto a still other related art.

FIG. 21 is a view illustrating a BB frame configuration method accordingto an embodiment of the present invention.

FIG. 22 is a view illustrating BB frames configured using the BB frameconfiguration method according to an embodiment of the presentinvention.

FIG. 23 is a view illustrating a result of comparing overheads ofvarious BB frame configuration methods.

FIG. 24 illustrates a method of transmitting broadcast signal accordingto an embodiment of the present invention.

FIG. 25 illustrates a method of receiving broadcast signal according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although most terms used in the present invention have been selectedfrom general ones widely used in the art, some terms have beenarbitrarily selected by the applicant and their meanings are explainedin detail in the following description as needed. Thus, the presentinvention should be understood based upon the intended meanings of theterms rather than their simple names or meanings.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, aUHDTV service, etc. The present invention may process broadcast signalsfor the future broadcast services through non-MIMO (Multiple InputMultiple Output) or MIMO according to one embodiment. A non-MIMO schemeaccording to an embodiment of the present invention may include a MISO(Multiple Input Single Output) scheme, a SISO (Single Input SingleOutput) scheme, etc.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas.

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

The apparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can includean input formatting module 1000, a coding & modulation module 1100, aframe structure module 1200, a waveform generation module 1300 and asignaling generation module 1400. A description will be given of theoperation of each module of the apparatus for transmitting broadcastsignals.

Referring to FIG. 1, the apparatus for transmitting broadcast signalsfor future broadcast services according to an embodiment of the presentinvention can receive MPEG-TSs, IP streams (v4/v6) and generic streams(GSs) as an input signal. In addition, the apparatus for transmittingbroadcast signals can receive management information about theconfiguration of each stream constituting the input signal and generatea final physical layer signal with reference to the received managementinformation.

The input formatting module 1000 according to an embodiment of thepresent invention can classify the input streams on the basis of astandard for coding and modulation or services or service components andoutput the input streams as a plurality of logical data pipes (or datapipes or DP data). The data pipe is a logical channel in the physicallayer that carries service data or related metadata, which may carry oneor multiple service(s) or service component(s). In addition, datatransmitted through each data pipe may be called DP data.

In addition, the input formatting module 1000 according to an embodimentof the present invention can divide each data pipe into blocks necessaryto perform coding and modulation and carry out processes necessary toincrease transmission efficiency or to perform scheduling. Details ofoperations of the input formatting module 1000 will be described later.

The coding & modulation module 1100 according to an embodiment of thepresent invention can perform forward error correction (FEC) encoding oneach data pipe received from the input formatting module 1000 such thatan apparatus for receiving broadcast signals can correct an error thatmay be generated on a transmission channel. In addition, the coding &modulation module 1100 according to an embodiment of the presentinvention can convert FEC output bit data to symbol data and interleavethe symbol data to correct burst error caused by a channel. As shown inFIG. 1, the coding & modulation module 1100 according to an embodimentof the present invention can divide the processed data such that thedivided data can be output through data paths for respective antennaoutputs in order to transmit the data through two or more Tx antennas.

The frame structure module 1200 according to an embodiment of thepresent invention can map the data output from the coding & modulationmodule 1100 to signal frames. The frame structure module 1200 accordingto an embodiment of the present invention can perform mapping usingscheduling information output from the input formatting module 1000 andinterleave data in the signal frames in order to obtain additionaldiversity gain.

The waveform generation module 1300 according to an embodiment of thepresent invention can convert the signal frames output from the framestructure module 1200 into a signal for transmission. In this case, thewaveform generation module 1300 according to an embodiment of thepresent invention can insert a preamble signal (or preamble) into thesignal for detection of the transmission apparatus and insert areference signal for estimating a transmission channel to compensate fordistortion into the signal. In addition, the waveform generation module1300 according to an embodiment of the present invention can provide aguard interval and insert a specific sequence into the same in order tooffset the influence of channel delay spread due to multi-pathreception. Additionally, the waveform generation module 1300 accordingto an embodiment of the present invention can perform a procedurenecessary for efficient transmission in consideration of signalcharacteristics such as a peak-to-average power ratio of the outputsignal.

The signaling generation module 1400 according to an embodiment of thepresent invention generates final physical layer signaling informationusing the input management information and information generated by theinput formatting module 1000, coding & modulation module 1100 and framestructure module 1200. Accordingly, a reception apparatus according toan embodiment of the present invention can decode a received signal bydecoding the signaling information.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to one embodiment of the presentinvention can provide terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc. Accordingly, the apparatus for transmittingbroadcast signals for future broadcast services according to oneembodiment of the present invention can multiplex signals for differentservices in the time domain and transmit the same.

FIGS. 2, 3 and 4 illustrate the input formatting module 1000 accordingto embodiments of the present invention. A description will be given ofeach figure.

FIG. 2 illustrates an input formatting module according to oneembodiment of the present invention. FIG. 2 shows an input formattingmodule when the input signal is a single input stream.

Referring to FIG. 2, the input formatting module according to oneembodiment of the present invention can include a mode adaptation module2000 and a stream adaptation module 2100.

As shown in FIG. 2, the mode adaptation module 2000 can include an inputinterface block 2010, a CRC-8 encoder block 2020 and a BB headerinsertion block 2030. Description will be given of each block of themode adaptation module 2000.

The input interface block 2010 can divide the single input stream inputthereto into data pieces each having the length of a baseband (BB) frameused for FEC (BCH/LDPC) which will be performed later and output thedata pieces.

The CRC-8 encoder block 2020 can perform CRC encoding on BB frame datato add redundancy data thereto.

The BB header insertion block 2030 can insert, into the BB frame data, aheader including information such as mode adaptation type (TS/GS/IP), auser packet length, a data field length, user packet sync byte, startaddress of user packet sync byte in data field, a high efficiency modeindicator, an input stream synchronization field, etc.

As shown in FIG. 2, the stream adaptation module 2100 can include apadding insertion block 2110 and a BB scrambler block 2120. Descriptionwill be given of each block of the stream adaptation module 2100.

If data received from the mode adaptation module 2000 has a lengthshorter than an input data length necessary for FEC encoding, thepadding insertion block 2110 can insert a padding bit into the data suchthat the data has the input data length and output the data includingthe padding bit.

The BB scrambler block 2120 can randomize the input bit stream byperforming an XOR operation on the input bit stream and a pseudo randombinary sequence (PRBS).

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

As shown in FIG. 2, the input formatting module can finally output datapipes to the coding & modulation module.

FIG. 3 illustrates an input formatting module according to anotherembodiment of the present invention. FIG. 3 shows a mode adaptationmodule 3000 of the input formatting module when the input signalcorresponds to multiple input streams.

The mode adaptation module 3000 of the input formatting module forprocessing the multiple input streams can independently process themultiple input streams.

Referring to FIG. 3, the mode adaptation module 3000 for respectivelyprocessing the multiple input streams can include input interfaceblocks, input stream synchronizer blocks 3100, compensating delay blocks3200, null packet deletion blocks 3300, CRC-8 encoder blocks and BBheader insertion blocks. Description will be given of each block of themode adaptation module 3000.

Operations of the input interface block, CRC-8 encoder block and BBheader insertion block correspond to those of the input interface block,CRC-8 encoder block and BB header insertion block described withreference to FIG. 2 and thus description thereof is omitted.

The input stream synchronizer block 3100 can transmit input stream clockreference (ISCR) information to generate timing information necessaryfor the apparatus for receiving broadcast signals to restore the TSs orGSs.

The compensating delay block 3200 can delay input data and output thedelayed input data such that the apparatus for receiving broadcastsignals can synchronize the input data if a delay is generated betweendata pipes according to processing of data including the timinginformation by the transmission apparatus.

The null packet deletion block 3300 can delete unnecessarily transmittedinput null packets from the input data, insert the number of deletednull packets into the input data based on positions in which the nullpackets are deleted and transmit the input data.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 4 illustrates an input formatting module according to anotherembodiment of the present invention.

Specifically, FIG. 4 illustrates a stream adaptation module of the inputformatting module when the input signal corresponds to multiple inputstreams.

The stream adaptation module of the input formatting module when theinput signal corresponds to multiple input streams can include ascheduler 4000, a 1-frame delay block 4100, an in-band signaling orpadding insertion block 4200, a physical layer signaling generationblock 4300 and a BB scrambler block 4400. Description will be given ofeach block of the stream adaptation module.

The scheduler 4000 can perform scheduling for a MIMO system usingmultiple antennas having dual polarity. In addition, the scheduler 4000can generate parameters for use in signal processing blocks for antennapaths, such as a bit-to-cell demux block, a cell interleaver block, atime interleaver block, etc. included in the coding & modulation moduleillustrated in FIG. 1.

The 1-frame delay block 4100 can delay the input data by onetransmission frame such that scheduling information about the next framecan be transmitted through the current frame for in-band signalinginformation to be inserted into the data pipes.

The in-band signaling or padding insertion block 4200 can insertundelayed physical layer signaling (PLS)-dynamic signaling informationinto the data delayed by one transmission frame. In this case, thein-band signaling or padding insertion block 4200 can insert a paddingbit when a space for padding is present or insert in-band signalinginformation into the padding space. In addition, the scheduler 4000 canoutput physical layer signaling-dynamic signaling information about thecurrent frame separately from in-band signaling information.Accordingly, a cell mapper, which will be described later, can map inputcells according to scheduling information output from the scheduler4000.

The physical layer signaling generation block 4300 can generate physicallayer signaling data which will be transmitted through a preamble symbolof a transmission frame or spread and transmitted through a data symbolother than the in-band signaling information. In this case, the physicallayer signaling data according to an embodiment of the present inventioncan be referred to as signaling information. Furthermore, the physicallayer signaling data according to an embodiment of the present inventioncan be divided into PLS-pre information and PLS-post information. ThePLS-pre information can include parameters necessary to encode thePLS-post information and static PLS signaling data and the PLS-postinformation can include parameters necessary to encode the data pipes.The parameters necessary to encode the data pipes can be classified intostatic PLS signaling data and dynamic PLS signaling data. The static PLSsignaling data is a parameter commonly applicable to all frames includedin a super-frame and can be changed on a super-frame basis. The dynamicPLS signaling data is a parameter differently applicable to respectiveframes included in a super-frame and can be changed on a frame-by-framebasis. Accordingly, the reception apparatus can acquire the PLS-postinformation by decoding the PLS-pre information and decode desired datapipes by decoding the PLS-post information.

The BB scrambler block 4400 can generate a pseudo-random binary sequence(PRBS) and perform an XOR operation on the PRBS and the input bitstreams to decrease the peak-to-average power ratio (PAPR) of the outputsignal of the waveform generation block. As shown in FIG. 4, scramblingof the BB scrambler block 4400 is applicable to both data pipes andphysical layer signaling information.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to designer.

As shown in FIG. 4, the stream adaptation module can finally output thedata pipes to the coding & modulation module.

FIG. 5 illustrates a coding & modulation module according to anembodiment of the present invention.

The coding & modulation module shown in FIG. 5 corresponds to anembodiment of the coding & modulation module illustrated in FIG. 1.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS (quality of service) depends on characteristics of a serviceprovided by the apparatus for transmitting broadcast signals for futurebroadcast services according to an embodiment of the present invention,data corresponding to respective services needs to be processed throughdifferent schemes. Accordingly, the coding & modulation module accordingto an embodiment of the present invention can independently process datapipes input thereto by independently applying SISO, MISO and MIMOschemes to the data pipes respectively corresponding to data paths.Consequently, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can control QoS for each service or service componenttransmitted through each data pipe.

Accordingly, the coding & modulation module according to an embodimentof the present invention can include a first block 5000 for SISO, asecond block 5100 for MISO, a third block 5200 for MIMO and a fourthblock 5300 for processing the PLS-pre/PLS-post information. The coding &modulation module illustrated in FIG. 5 is an exemplary and may includeonly the first block 5000 and the fourth block 5300, the second block5100 and the fourth block 5300 or the third block 5200 and the fourthblock 5300 according to design. That is, the coding & modulation modulecan include blocks for processing data pipes equally or differentlyaccording to design.

A description will be given of each block of the coding & modulationmodule.

The first block 5000 processes an input data pipe according to SISO andcan include an FEC encoder block 5010, a bit interleaver block 5020, abit-to-cell demux block 5030, a constellation mapper block 5040, a cellinterleaver block 5050 and a time interleaver block 5060.

The FEC encoder block 5010 can perform BCH encoding and LDPC encoding onthe input data pipe to add redundancy thereto such that the receptionapparatus can correct an error generated on a transmission channel.

The bit interleaver block 5020 can interleave bit streams of theFEC-encoded data pipe according to an interleaving rule such that thebit streams have robustness against burst error that may be generated onthe transmission channel. Accordingly, when deep fading or erasure isapplied to QAM symbols, errors can be prevented from being generated inconsecutive bits from among all codeword bits since interleaved bits aremapped to the QAM symbols.

The bit-to-cell demux block 5030 can determine the order of input bitstreams such that each bit in an FEC block can be transmitted withappropriate robustness in consideration of both the order of input bitstreams and a constellation mapping rule.

In addition, the bit interleaver block 5020 is located between the FECencoder block 5010 and the constellation mapper block 5040 and canconnect output bits of LDPC encoding performed by the FEC encoder block5010 to bit positions having different reliability values and optimalvalues of the constellation mapper in consideration of LDPC decoding ofthe apparatus for receiving broadcast signals. Accordingly, thebit-to-cell demux block 5030 can be replaced by a block having a similaror equal function.

The constellation mapper block 5040 can map a bit word input thereto toone constellation. In this case, the constellation mapper block 5040 canadditionally perform rotation & Q-delay. That is, the constellationmapper block 5040 can rotate input constellations according to arotation angle, divide the constellations into an in-phase component anda quadrature-phase component and delay only the quadrature-phasecomponent by an arbitrary value. Then, the constellation mapper block5040 can remap the constellations to new constellations using a pairedin-phase component and quadrature-phase component.

In addition, the constellation mapper block 5040 can move constellationpoints on a two-dimensional plane in order to find optimal constellationpoints. Through this process, capacity of the coding & modulation module1100 can be optimized. Furthermore, the constellation mapper block 5040can perform the above-described operation using IQ-balancedconstellation points and rotation. The constellation mapper block 5040can be replaced by a block having a similar or equal function.

The cell interleaver block 5050 can randomly interleave cellscorresponding to one FEC block and output the interleaved cells suchthat cells corresponding to respective FEC blocks can be output indifferent orders.

The time interleaver block 5060 can interleave cells belonging to aplurality of FEC blocks and output the interleaved cells. Accordingly,the cells corresponding to the FEC blocks are dispersed and transmittedin a period corresponding to a time interleaving depth and thusdiversity gain can be obtained.

The second block 5100 processes an input data pipe according to MISO andcan include the FEC encoder block, bit interleaver block, bit-to-celldemux block, constellation mapper block, cell interleaver block and timeinterleaver block in the same manner as the first block 5000. However,the second block 5100 is distinguished from the first block 5000 in thatthe second block 5100 further includes a MISO processing block 5110. Thesecond block 5100 performs the same procedure including the inputoperation to the time interleaver operation as those of the first block5000 and thus description of the corresponding blocks is omitted.

The MISO processing block 5110 can encode input cells according to aMISO encoding matrix providing transmit diversity and outputMISO-processed data through two paths. MISO processing according to oneembodiment of the present invention can include OSTBC (orthogonal spacetime block coding)/OSFBC (orthogonal space frequency block coding,Alamouti coding).

The third block 5200 processes an input data pipe according to MIMO andcan include the FEC encoder block, bit interleaver block, bit-to-celldemux block, constellation mapper block, cell interleaver block and timeinterleaver block in the same manner as the second block 5100, as shownin FIG. 5. However, the data processing procedure of the third block5200 is different from that of the second block 5100 since the thirdblock 5200 includes a MIMO processing block 5220.

That is, in the third block 5200, basic roles of the FEC encoder blockand the bit interleaver block are identical to those of the first andsecond blocks 5000 and 5100 although functions thereof may be differentfrom those of the first and second blocks 5000 and 5100.

The bit-to-cell demux block 5210 can generate as many output bit streamsas input bit streams of MIMO processing and output the output bitstreams through MIMO paths for MIMO processing. In this case, thebit-to-cell demux block 5210 can be designed to optimize the decodingperformance of the reception apparatus in consideration ofcharacteristics of LDPC and MIMO processing.

Basic roles of the constellation mapper block, cell interleaver blockand time interleaver block are identical to those of the first andsecond blocks 5000 and 5100 although functions thereof may be differentfrom those of the first and second blocks 5000 and 5100. As shown inFIG. 5, as many constellation mapper blocks, cell interleaver blocks andtime interleaver blocks as the number of MIMO paths for MIMO processingcan be present. In this case, the constellation mapper blocks, cellinterleaver blocks and time interleaver blocks can operate equally orindependently for data input through the respective paths.

The MIMO processing block 5220 can perform MIMO processing on two inputcells using a MIMO encoding matrix and output the MIMO-processed datathrough two paths. The MIMO encoding matrix according to an embodimentof the present invention can include spatial multiplexing, Golden code,full-rate full diversity code, linear dispersion code, etc.

The fourth block 5300 processes the PLS-pre/PLS-post information and canperform SISO or MISO processing.

The basic roles of the bit interleaver block, bit-to-cell demux block,constellation mapper block, cell interleaver block, time interleaverblock and MISO processing block included in the fourth block 5300correspond to those of the second block 5100 although functions thereofmay be different from those of the second block 5100.

A shortened/punctured FEC encoder block 5310 included in the fourthblock 5300 can process PLS data using an FEC encoding scheme for a PLSpath provided for a case in which the length of input data is shorterthan a length necessary to perform FEC encoding. Specifically, theshortened/punctured FEC encoder block 5310 can perform BCH encoding oninput bit streams, pad 0s corresponding to a desired input bit streamlength necessary for normal LDPC encoding, carry out LDPC encoding andthen remove the padded 0s to puncture parity bits such that an effectivecode rate becomes equal to or lower than the data pipe rate.

The blocks included in the first block 5000 to fourth block 5300 may beomitted or replaced by blocks having similar or identical functionsaccording to design.

As illustrated in FIG. 5, the coding & modulation module can output thedata pipes (or DP data), PLS-pre information and PLS-post informationprocessed for the respective paths to the frame structure module.

FIG. 6 illustrates a frame structure module according to one embodimentof the present invention.

The frame structure module shown in FIG. 6 corresponds to an embodimentof the frame structure module 1200 illustrated in FIG. 1.

The frame structure module according to one embodiment of the presentinvention can include at least one cell-mapper 6000, at least one delaycompensation module 6100 and at least one block interleaver 6200. Thenumber of cell mappers 6000, delay compensation modules 6100 and blockinterleavers 6200 can be changed. A description will be given of eachmodule of the frame structure block.

The cell-mapper 6000 can allocate (or arrange) cells corresponding toSISO-, MISO- or MIMO-processed data pipes output from the coding &modulation module, cells corresponding to common data commonlyapplicable to the data pipes and cells corresponding to thePLS-pre/PLS-post information to signal frames according to schedulinginformation. The common data refers to signaling information commonlyapplied to all or some data pipes and can be transmitted through aspecific data pipe. The data pipe through which the common data istransmitted can be referred to as a common data pipe and can be changedaccording to design.

When the apparatus for transmitting broadcast signals according to anembodiment of the present invention uses two output antennas andAlamouti coding is used for MISO processing, the cell-mapper 6000 canperform pair-wise cell mapping in order to maintain orthogonalityaccording to Alamouti encoding. That is, the cell-mapper 6000 canprocess two consecutive cells of the input cells as one unit and map (orarrange) the unit to a frame. Accordingly, paired cells in an input pathcorresponding to an output path of each antenna can be allocated (orarranged) to neighboring positions in a transmission frame.

The delay compensation block 6100 can obtain PLS data corresponding tothe current transmission frame by delaying input PLS data cells for thenext transmission frame by one frame. In this case, the PLS datacorresponding to the current frame can be transmitted through a preamblepart in the current signal frame and PLS data corresponding to the nextsignal frame can be transmitted through a preamble part in the currentsignal frame or in-band signaling in each data pipe of the currentsignal frame. This can be changed by the designer.

The block interleaver 6200 can obtain additional diversity gain byinterleaving cells in a transport block corresponding to the unit of asignal frame. In addition, the block interleaver 6200 can performinterleaving by processing two consecutive cells of the input cells asone unit when the above-described pair-wise cell mapping is performed.Accordingly, cells output from the block interleaver 6200 can be twoconsecutive identical cells.

When pair-wise mapping and pair-wise interleaving are performed, atleast one cell mapper and at least one block interleaver can operateequally or independently for data input through the paths.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

As illustrated in FIG. 6, the frame structure module can output at leastone signal frame to the waveform generation module.

FIG. 7 illustrates a waveform generation module according to anembodiment of the present invention.

The waveform generation module illustrated in FIG. 7 corresponds to anembodiment of the waveform generation module 1300 described withreference to FIG. 1.

The waveform generation module according to an embodiment of the presentinvention can modulate and transmit as many signal frames as the numberof antennas for receiving and outputting signal frames output from theframe structure module illustrated in FIG. 6.

Specifically, the waveform generation module illustrated in FIG. 7 is anembodiment of a waveform generation module of an apparatus fortransmitting broadcast signals using m Tx antennas and can include mprocessing blocks for modulating and outputting frames corresponding tom paths. The m processing blocks can perform the same processingprocedure. A description will be given of operation of the firstprocessing block 7000 from among the m processing blocks.

The first processing block 7000 can include a reference signal & PAPRreduction block 7100, an inverse waveform transform block 7200, a PAPRreduction in time block 7300, a guard sequence insertion block 7400, apreamble insertion block 7500, a waveform processing block 7600, othersystem insertion block 7700 and a DAC (digital analog converter) block7800.

The reference signal insertion & PAPR reduction block 7100 can insert areference signal into a predetermined position of each signal block andapply a PAPR reduction scheme to reduce a PAPR in the time domain. If abroadcast transmission/reception system according to an embodiment ofthe present invention corresponds to an OFDM system, the referencesignal insertion & PAPR reduction block 7100 can use a method ofreserving some active subcarriers rather than using the same. Inaddition, the reference signal insertion & PAPR reduction block 7100 maynot use the PAPR reduction scheme as an optional feature according tobroadcast transmission/reception system.

The inverse waveform transform block 7200 can transform an input signalin a manner of improving transmission efficiency and flexibility inconsideration of transmission channel characteristics and systemarchitecture. If the broadcast transmission/reception system accordingto an embodiment of the present invention corresponds to an OFDM system,the inverse waveform transform block 7200 can employ a method oftransforming a frequency domain signal into a time domain signal throughinverse FFT operation. If the broadcast transmission/reception systemaccording to an embodiment of the present invention corresponds to asingle carrier system, the inverse waveform transform block 7200 may notbe used in the waveform generation module.

The PAPR reduction in time block 7300 can use a method for reducing PAPRof an input signal in the time domain. If the broadcasttransmission/reception system according to an embodiment of the presentinvention corresponds to an OFDM system, the PAPR reduction in timeblock 7300 may use a method of simply clipping peak amplitude.Furthermore, the PAPR reduction in time block 7300 may not be used inthe broadcast transmission/reception system according to an embodimentof the present invention since it is an optional feature.

The guard sequence insertion block 7400 can provide a guard intervalbetween neighboring signal blocks and insert a specific sequence intothe guard interval as necessary in order to minimize the influence ofdelay spread of a transmission channel. Accordingly, the receptionapparatus can easily perform synchronization or channel estimation. Ifthe broadcast transmission/reception system according to an embodimentof the present invention corresponds to an OFDM system, the guardsequence insertion block 7400 may insert a cyclic prefix into a guardinterval of an OFDM symbol.

The preamble insertion block 7500 can insert a signal of a known type(e.g. the preamble or preamble symbol) agreed upon between thetransmission apparatus and the reception apparatus into a transmissionsignal such that the reception apparatus can rapidly and efficientlydetect a target system signal. If the broadcast transmission/receptionsystem according to an embodiment of the present invention correspondsto an OFDM system, the preamble insertion block 7500 can define a signalframe composed of a plurality of OFDM symbols and insert a preamblesymbol into the beginning of each signal frame. That is, the preamblecarries basic PLS data and is located in the beginning of a signalframe.

The waveform processing block 7600 can perform waveform processing on aninput baseband signal such that the input baseband signal meets channeltransmission characteristics. The waveform processing block 7600 may usea method of performing square-root-raised cosine (SRRC) filtering toobtain a standard for out-of-band emission of a transmission signal. Ifthe broadcast transmission/reception system according to an embodimentof the present invention corresponds to a multi-carrier system, thewaveform processing block 7600 may not be used.

The other system insertion block 7700 can multiplex signals of aplurality of broadcast transmission/reception systems in the time domainsuch that data of two or more different broadcast transmission/receptionsystems providing broadcast services can be simultaneously transmittedin the same RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc. Datarelated to respective broadcast services can be transmitted throughdifferent frames.

The DAC block 7800 can convert an input digital signal into an analogsignal and output the analog signal. The signal output from the DACblock 7800 can be transmitted through m output antennas. A Tx antennaaccording to an embodiment of the present invention can have vertical orhorizontal polarity.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 8 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention cancorrespond to the apparatus for transmitting broadcast signals forfuture broadcast services, described with reference to FIG. 1. Theapparatus for receiving broadcast signals for future broadcast servicesaccording to an embodiment of the present invention can include asynchronization & demodulation module 8000, a frame parsing module 8100,a demapping & decoding module 8200, an output processor 8300 and asignaling decoding module 8400. A description will be given of operationof each module of the apparatus for receiving broadcast signals.

The synchronization & demodulation module 8000 can receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the apparatus for receivingbroadcast signals and carry out demodulation corresponding to a reverseprocedure of the procedure performed by the apparatus for transmittingbroadcast signals.

The frame parsing module 8100 can parse input signal frames and extractdata through which a service selected by a user is transmitted. If theapparatus for transmitting broadcast signals performs interleaving, theframe parsing module 8100 can carry out deinterleaving corresponding toa reverse procedure of interleaving. In this case, the positions of asignal and data that need to be extracted can be obtained by decodingdata output from the signaling decoding module 8400 to restorescheduling information generated by the apparatus for transmittingbroadcast signals.

The demapping & decoding module 8200 can convert the input signals intobit domain data and then deinterleave the same as necessary. Thedemapping & decoding module 8200 can perform demapping for mappingapplied for transmission efficiency and correct an error generated on atransmission channel through decoding. In this case, the demapping &decoding module 8200 can obtain transmission parameters necessary fordemapping and decoding by decoding the data output from the signalingdecoding module 8400.

The output processor 8300 can perform reverse procedures of variouscompression/signal processing procedures which are applied by theapparatus for transmitting broadcast signals to improve transmissionefficiency. In this case, the output processor 8300 can acquirenecessary control information from data output from the signalingdecoding module 8400. The output of the output processor 8300corresponds to a signal input to the apparatus for transmittingbroadcast signals and may be MPEG-TSs, IP streams (v4 or v6) and genericstreams.

The signaling decoding module 8400 can obtain PLS information from thesignal demodulated by the synchronization & demodulation module 8000. Asdescribed above, the frame parsing module 8100, demapping & decodingmodule 8200 and output processor 8300 can execute functions thereofusing the data output from the signaling decoding module 8400.

FIG. 9 illustrates a synchronization & demodulation module according toan embodiment of the present invention.

The synchronization & demodulation module shown in FIG. 9 corresponds toan embodiment of the synchronization & demodulation module describedwith reference to FIG. 8. The synchronization & demodulation moduleshown in FIG. 9 can perform a reverse operation of the operation of thewaveform generation module illustrated in FIG. 7.

As shown in FIG. 9, the synchronization & demodulation module accordingto an embodiment of the present invention corresponds to asynchronization & demodulation module of an apparatus for receivingbroadcast signals using m Rx antennas and can include m processingblocks for demodulating signals respectively input through m paths. Them processing blocks can perform the same processing procedure. Adescription will be given of operation of the first processing block9000 from among the m processing blocks.

The first processing block 9000 can include a tuner 9100, an ADC block9200, a preamble detector 9300, a guard sequence detector 9400, awaveform transform block 9500, a time/frequency synchronization block9600, a reference signal detector 9700, a channel equalizer 9800 and aninverse waveform transform block 9900.

The tuner 9100 can select a desired frequency band, compensate for themagnitude of a received signal and output the compensated signal to theADC block 9200.

The ADC block 9200 can convert the signal output from the tuner 9100into a digital signal.

The preamble detector 9300 can detect a preamble (or preamble signal orpreamble symbol) in order to check whether or not the digital signal isa signal of the system corresponding to the apparatus for receivingbroadcast signals. In this case, the preamble detector 9300 can decodebasic transmission parameters received through the preamble.

The guard sequence detector 9400 can detect a guard sequence in thedigital signal. The time/frequency synchronization block 9600 canperform time/frequency synchronization using the detected guard sequenceand the channel equalizer 9800 can estimate a channel through areceived/restored sequence using the detected guard sequence.

The waveform transform block 9500 can perform a reverse operation ofinverse waveform transform when the apparatus for transmitting broadcastsignals has performed inverse waveform transform. When the broadcasttransmission/reception system according to one embodiment of the presentinvention is a multi-carrier system, the waveform transform block 9500can perform FFT. Furthermore, when the broadcast transmission/receptionsystem according to an embodiment of the present invention is a singlecarrier system, the waveform transform block 9500 may not be used if areceived time domain signal is processed in the frequency domain orprocessed in the time domain.

The time/frequency synchronization block 9600 can receive output data ofthe preamble detector 9300, guard sequence detector 9400 and referencesignal detector 9700 and perform time synchronization and carrierfrequency synchronization including guard sequence detection and blockwindow positioning on a detected signal. Here, the time/frequencysynchronization block 9600 can feed back the output signal of thewaveform transform block 9500 for frequency synchronization.

The reference signal detector 9700 can detect a received referencesignal. Accordingly, the apparatus for receiving broadcast signalsaccording to an embodiment of the present invention can performsynchronization or channel estimation.

The channel equalizer 9800 can estimate a transmission channel from eachTx antenna to each Rx antenna from the guard sequence or referencesignal and perform channel equalization for received data using theestimated channel.

The inverse waveform transform block 9900 may restore the originalreceived data domain when the waveform transform block 9500 performswaveform transform for efficient synchronization and channelestimation/equalization. If the broadcast transmission/reception systemaccording to an embodiment of the present invention is a single carriersystem, the waveform transform block 9500 can perform FFT in order tocarry out synchronization/channel estimation/equalization in thefrequency domain and the inverse waveform transform block 9900 canperform IFFT on the channel-equalized signal to restore transmitted datasymbols. If the broadcast transmission/reception system according to anembodiment of the present invention is a multi-carrier system, theinverse waveform transform block 9900 may not be used.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 10 illustrates a frame parsing module according to an embodiment ofthe present invention.

The frame parsing module illustrated in FIG. 10 corresponds to anembodiment of the frame parsing module described with reference to FIG.8. The frame parsing module shown in FIG. 10 can perform a reverseoperation of the operation of the frame structure module illustrated inFIG. 6.

As shown in FIG. 10, the frame parsing module according to an embodimentof the present invention can include at least one block interleaver10000 and at least one cell demapper 10100.

The block interleaver 10000 can deinterleave data input through datapaths of the m Rx antennas and processed by the synchronization &demodulation module on a signal block basis. In this case, if theapparatus for transmitting broadcast signals performs pair-wiseinterleaving as illustrated in FIG. 8, the block interleaver 10000 canprocess two consecutive pieces of data as a pair for each input path.Accordingly, the block interleaver 10000 can output two consecutivepieces of data even when deinterleaving has been performed. Furthermore,the block interleaver 10000 can perform a reverse operation of theinterleaving operation performed by the apparatus for transmittingbroadcast signals to output data in the original order.

The cell demapper 10100 can extract cells corresponding to common data,cells corresponding to data pipes and cells corresponding to PLS datafrom received signal frames. The cell demapper 10100 can merge datadistributed and transmitted and output the same as a stream asnecessary. When two consecutive pieces of cell input data are processedas a pair and mapped in the apparatus for transmitting broadcastsignals, as shown in FIG. 6, the cell demapper 10100 can performpair-wise cell demapping for processing two consecutive input cells asone unit as a reverse procedure of the mapping operation of theapparatus for transmitting broadcast signals.

In addition, the cell demapper 10100 can extract PLS signaling datareceived through the current frame as PLS-pre & PLS-post data and outputthe PLS-pre & PLS-post data.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 11 illustrates a demapping & decoding module according to anembodiment of the present invention.

The demapping & decoding module shown in FIG. 11 corresponds to anembodiment of the demapping & decoding module illustrated in FIG. 8. Thedemapping & decoding module shown in FIG. 11 can perform a reverseoperation of the operation of the coding & modulation module illustratedin FIG. 5.

The coding & modulation module of the apparatus for transmittingbroadcast signals according to an embodiment of the present inventioncan process input data pipes by independently applying SISO, MISO andMIMO thereto for respective paths, as described above. Accordingly, thedemapping & decoding module illustrated in FIG. 11 can include blocksfor processing data output from the frame parsing module according toSISO, MISO and MIMO in response to the apparatus for transmittingbroadcast signals.

As shown in FIG. 11, the demapping & decoding module according to anembodiment of the present invention can include a first block 11000 forSISO, a second block 11100 for MISO, a third block 11200 for MIMO and afourth block 11300 for processing the PLS-pre/PLS-post information. Thedemapping & decoding module shown in FIG. 11 is exemplary and mayinclude only the first block 11000 and the fourth block 11300, only thesecond block 11100 and the fourth block 11300 or only the third block11200 and the fourth block 11300 according to design. That is, thedemapping & decoding module can include blocks for processing data pipesequally or differently according to design.

A description will be given of each block of the demapping & decodingmodule.

The first block 11000 processes an input data pipe according to SISO andcan include a time deinterleaver block 11010, a cell deinterleaver block11020, a constellation demapper block 11030, a cell-to-bit mux block11040, a bit deinterleaver block 11050 and an FEC decoder block 11060.

The time deinterleaver block 11010 can perform a reverse process of theprocess performed by the time interleaver block 5060 illustrated in FIG.5. That is, the time deinterleaver block 11010 can deinterleave inputsymbols interleaved in the time domain into original positions thereof.

The cell deinterleaver block 11020 can perform a reverse process of theprocess performed by the cell interleaver block 5050 illustrated in FIG.5. That is, the cell deinterleaver block 11020 can deinterleavepositions of cells spread in one FEC block into original positionsthereof.

The constellation demapper block 11030 can perform a reverse process ofthe process performed by the constellation mapper block 5040 illustratedin FIG. 5. That is, the constellation demapper block 11030 can demap asymbol domain input signal to bit domain data. In addition, theconstellation demapper block 11030 may perform hard decision and outputdecided bit data. Furthermore, the constellation demapper block 11030may output a log-likelihood ratio (LLR) of each bit, which correspondsto a soft decision value or probability value. If the apparatus fortransmitting broadcast signals applies a rotated constellation in orderto obtain additional diversity gain, the constellation demapper block11030 can perform 2-dimensional LLR demapping corresponding to therotated constellation. Here, the constellation demapper block 11030 cancalculate the LLR such that a delay applied by the apparatus fortransmitting broadcast signals to the I or Q component can becompensated.

The cell-to-bit mux block 11040 can perform a reverse process of theprocess performed by the bit-to-cell demux block 5030 illustrated inFIG. 5. That is, the cell-to-bit mux block 11040 can restore bit datamapped by the bit-to-cell demux block 5030 to the original bit streams.

The bit deinterleaver block 11050 can perform a reverse process of theprocess performed by the bit interleaver 5020 illustrated in FIG. 5.That is, the bit deinterleaver block 11050 can deinterleave the bitstreams output from the cell-to-bit mux block 11040 in the originalorder.

The FEC decoder block 11060 can perform a reverse process of the processperformed by the FEC encoder block 5010 illustrated in FIG. 5. That is,the FEC decoder block 11060 can correct an error generated on atransmission channel by performing LDPC decoding and BCH decoding.

The second block 11100 processes an input data pipe according to MISOand can include the time deinterleaver block, cell deinterleaver block,constellation demapper block, cell-to-bit mux block, bit deinterleaverblock and FEC decoder block in the same manner as the first block 11000,as shown in FIG. 11. However, the second block 11100 is distinguishedfrom the first block 11000 in that the second block 11100 furtherincludes a MISO decoding block 11110. The second block 11100 performsthe same procedure including time deinterleaving operation to outputtingoperation as the first block 11000 and thus description of thecorresponding blocks is omitted.

The MISO decoding block 11110 can perform a reverse operation of theoperation of the MISO processing block 5110 illustrated in FIG. 5. Ifthe broadcast transmission/reception system according to an embodimentof the present invention uses STBC, the MISO decoding block 11110 canperform Alamouti decoding.

The third block 11200 processes an input data pipe according to MIMO andcan include the time deinterleaver block, cell deinterleaver block,constellation demapper block, cell-to-bit mux block, bit deinterleaverblock and FEC decoder block in the same manner as the second block11100, as shown in FIG. 11. However, the third block 11200 isdistinguished from the second block 11100 in that the third block 11200further includes a MIMO decoding block 11210. The basic roles of thetime deinterleaver block, cell deinterleaver block, constellationdemapper block, cell-to-bit mux block and bit deinterleaver blockincluded in the third block 11200 are identical to those of thecorresponding blocks included in the first and second blocks 11000 and11100 although functions thereof may be different from the first andsecond blocks 11000 and 11100.

The MIMO decoding block 11210 can receive output data of the celldeinterleaver for input signals of the m Rx antennas and perform MIMOdecoding as a reverse operation of the operation of the MIMO processingblock 5220 illustrated in FIG. 5. The MIMO decoding block 11210 canperform maximum likelihood decoding to obtain optimal decodingperformance or carry out sphere decoding with reduced complexity.Otherwise, the MIMO decoding block 11210 can achieve improved decodingperformance by performing MMSE detection or carrying out iterativedecoding with MMSE detection.

The fourth block 11300 processes the PLS-pre/PLS-post information andcan perform SISO or MISO decoding. The fourth block 11300 can carry outa reverse process of the process performed by the fourth block 5300described with reference to FIG. 5.

The basic roles of the time deinterleaver block, cell deinterleaverblock, constellation demapper block, cell-to-bit mux block and bitdeinterleaver block included in the fourth block 11300 are identical tothose of the corresponding blocks of the first, second and third blocks11000, 11100 and 11200 although functions thereof may be different fromthe first, second and third blocks 11000, 11100 and 11200.

The shortened/punctured FEC decoder 11310 included in the fourth block11300 can perform a reverse process of the process performed by theshortened/punctured FEC encoder block 5310 described with reference toFIG. 5. That is, the shortened/punctured FEC decoder 11310 can performde-shortening and de-puncturing on data shortened/punctured according toPLS data length and then carry out FEC decoding thereon. In this case,the FEC decoder used for data pipes can also be used for PLS.Accordingly, additional FEC decoder hardware for the PLS only is notneeded and thus system design is simplified and efficient coding isachieved.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

The demapping & decoding module according to an embodiment of thepresent invention can output data pipes and PLS information processedfor the respective paths to the output processor, as illustrated in FIG.11.

FIGS. 12 and 13 illustrate output processors according to embodiments ofthe present invention.

FIG. 12 illustrates an output processor according to an embodiment ofthe present invention. The output processor illustrated in FIG. 12corresponds to an embodiment of the output processor illustrated in FIG.8. The output processor illustrated in FIG. 12 receives a single datapipe output from the demapping & decoding module and outputs a singleoutput stream. The output processor can perform a reverse operation ofthe operation of the input formatting module illustrated in FIG. 2.

The output processor shown in FIG. 12 can include a BB scrambler block12000, a padding removal block 12100, a CRC-8 decoder block 12200 and aBB frame processor block 12300.

The BB scrambler block 12000 can descramble an input bit stream bygenerating the same PRBS as that used in the apparatus for transmittingbroadcast signals for the input bit stream and carrying out an XORoperation on the PRBS and the bit stream.

The padding removal block 12100 can remove padding bits inserted by theapparatus for transmitting broadcast signals as necessary.

The CRC-8 decoder block 12200 can check a block error by performing CRCdecoding on the bit stream received from the padding removal block12100.

The BB frame processor block 12300 can decode information transmittedthrough a BB frame header and restore MPEG-TSs, IP streams (v4 or v6) orgeneric streams using the decoded information.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 13 illustrates an output processor according to another embodimentof the present invention. The output processor shown in FIG. 13corresponds to an embodiment of the output processor illustrated in FIG.8. The output processor shown in FIG. 13 receives multiple data pipesoutput from the demapping & decoding module. Decoding multiple datapipes can include a process of merging common data commonly applicableto a plurality of data pipes and data pipes related thereto and decodingthe same or a process of simultaneously decoding a plurality of servicesor service components (including a scalable video service) by theapparatus for receiving broadcast signals.

The output processor shown in FIG. 13 can include a BB descramblerblock, a padding removal block, a CRC-8 decoder block and a BB frameprocessor block as the output processor illustrated in FIG. 12. Thebasic roles of these blocks correspond to those of the blocks describedwith reference to FIG. 12 although operations thereof may differ fromthose of the blocks illustrated in FIG. 12.

A de-jitter buffer block 13000 included in the output processor shown inFIG. 13 can compensate for a delay, inserted by the apparatus fortransmitting broadcast signals for synchronization of multiple datapipes, according to a restored TTO (time to output) parameter.

A null packet insertion block 13100 can restore a null packet removedfrom a stream with reference to a restored DNP (deleted null packet) andoutput common data.

A TS clock regeneration block 13200 can restore time synchronization ofoutput packets based on ISCR (input stream time reference) information.

A TS recombining block 13300 can recombine the common data and datapipes related thereto, output from the null packet insertion block13100, to restore the original MPEG-TSs, IP streams (v4 or v6) orgeneric streams. The TTO, DNT and ISCR information can be obtainedthrough the BB frame header.

An in-band signaling decoding block 13400 can decode and output in-bandphysical layer signaling information transmitted through a padding bitfield in each FEC frame of a data pipe.

The output processor shown in FIG. 13 can BB-descramble the PLS-preinformation and PLS-post information respectively input through aPLS-pre path and a PLS-post path and decode the descrambled data torestore the original PLS data. The restored PLS data is delivered to asystem controller included in the apparatus for receiving broadcastsignals. The system controller can provide parameters necessary for thesynchronization & demodulation module, frame parsing module, demapping &decoding module and output processor module of the apparatus forreceiving broadcast signals.

The above-described blocks may be omitted or replaced by blocks havingsimilar r identical functions according to design.

FIG. 14 illustrates a coding & modulation module according to anotherembodiment of the present invention.

The coding & modulation module shown in FIG. 14 corresponds to anotherembodiment of the coding & modulation module illustrated in FIGS. 1 to5.

To control QoS for each service or service component transmitted througheach data pipe, as described above with reference to FIG. 5, the coding& modulation module shown in FIG. 14 can include a first block 14000 forSISO, a second block 14100 for MISO, a third block 14200 for MIMO and afourth block 14300 for processing the PLS-pre/PLS-post information. Inaddition, the coding & modulation module can include blocks forprocessing data pipes equally or differently according to the design.The first to fourth blocks 14000 to 14300 shown in FIG. 14 are similarto the first to fourth blocks 5000 to 5300 illustrated in FIG. 5.

However, the first to fourth blocks 14000 to 14300 shown in FIG. 14 aredistinguished from the first to fourth blocks 5000 to 5300 illustratedin FIG. 5 in that a constellation mapper 14010 included in the first tofourth blocks 14000 to 14300 has a function different from the first tofourth blocks 5000 to 5300 illustrated in FIG. 5, a rotation & I/Qinterleaver block 14020 is present between the cell interleaver and thetime interleaver of the first to fourth blocks 14000 to 14300illustrated in FIG. 14 and the third block 14200 for MIMO has aconfiguration different from the third block 5200 for MIMO illustratedin FIG. 5. The following description focuses on these differencesbetween the first to fourth blocks 14000 to 14300 shown in FIG. 14 andthe first to fourth blocks 5000 to 5300 illustrated in FIG. 5.

The constellation mapper block 14010 shown in FIG. 14 can map an inputbit word to a complex symbol. However, the constellation mapper block14010 may not perform constellation rotation, differently from theconstellation mapper block shown in FIG. 5. The constellation mapperblock 14010 shown in FIG. 14 is commonly applicable to the first, secondand third blocks 14000, 14100 and 14200, as described above.

The rotation & I/Q interleaver block 14020 can independently interleavein-phase and quadrature-phase components of each complex symbol ofcell-interleaved data output from the cell interleaver and output thein-phase and quadrature-phase components on a symbol-by-symbol basis.The number of number of input data pieces and output data pieces of therotation & I/Q interleaver block 14020 is two or more which can bechanged by the designer. In addition, the rotation & I/Q interleaverblock 14020 may not interleave the in-phase component.

The rotation & I/Q interleaver block 14020 is commonly applicable to thefirst to fourth blocks 14000 to 14300, as described above. In this case,whether or not the rotation & I/Q interleaver block 14020 is applied tothe fourth block 14300 for processing the PLS-pre/post information canbe signaled through the above-described preamble.

The third block 14200 for MIMO can include a Q-block interleaver block14210 and a complex symbol generator block 14220, as illustrated in FIG.14.

The Q-block interleaver block 14210 can permute a parity part of anFEC-encoded FEC block received from the FEC encoder. Accordingly, aparity part of an LDPC H matrix can be made into a cyclic structure likean information part. The Q-block interleaver block 14210 can permute theorder of output bit blocks having Q size of the LDPC H matrix and thenperform row-column block interleaving to generate final bit streams.

The complex symbol generator block 14220 receives the bit streams outputfrom the Q-block interleaver block 14210, maps the bit streams tocomplex symbols and outputs the complex symbols. In this case, thecomplex symbol generator block 14220 can output the complex symbolsthrough at least two paths. This can be modified by the designer.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

The coding & modulation module according to another embodiment of thepresent invention, illustrated in FIG. 14, can output data pipes,PLS-pre information and PLS-post information processed for respectivepaths to the frame structure module.

FIG. 15 illustrates a demapping & decoding module according to anotherembodiment of the present invention.

The demapping & decoding module shown in FIG. 15 corresponds to anotherembodiment of the demapping & decoding module illustrated in FIG. 11.The demapping & decoding module shown in FIG. 15 can perform a reverseoperation of the operation of the coding & modulation module illustratedin FIG. 14.

As shown in FIG. 15, the demapping & decoding module according toanother embodiment of the present invention can include a first block15000 for SISO, a second block 11100 for MISO, a third block 15200 forMIMO and a fourth block 14300 for processing the PLS-pre/PLS-postinformation. In addition, the demapping & decoding module can includeblocks for processing data pipes equally or differently according todesign. The first to fourth blocks 15000 to 15300 shown in FIG. 15 aresimilar to the first to fourth blocks 11000 to 11300 illustrated in FIG.11.

However, the first to fourth blocks 15000 to 15300 shown in FIG. 15 aredistinguished from the first to fourth blocks 11000 to 11300 illustratedin FIG. 11 in that an I/Q deinterleaver and derotation block 15010 ispresent between the time interleaver and the cell deinterleaver of thefirst to fourth blocks 15000 to 15300, a constellation mapper 15010included in the first to fourth blocks 15000 to 15300 has a functiondifferent from the first to fourth blocks 11000 to 11300 illustrated inFIG. 11 and the third block 15200 for MIMO has a configuration differentfrom the third block 11200 for MIMO illustrated in FIG. 11. Thefollowing description focuses on these differences between the first tofourth blocks 15000 to 15300 shown in FIG. 15 and the first to fourthblocks 11000 to 11300 illustrated in FIG. 11.

The I/Q deinterleaver & derotation block 15010 can perform a reverseprocess of the process performed by the rotation & I/Q interleaver block14020 illustrated in FIG. 14. That is, the I/Q deinterleaver &derotation block 15010 can deinterleave I and Q componentsI/Q-interleaved and transmitted by the apparatus for transmittingbroadcast signals and derotate complex symbols having the restored I andQ components.

The I/Q deinterleaver & derotation block 15010 is commonly applicable tothe first to fourth blocks 15000 to 15300, as described above. In thiscase, whether or not the I/Q deinterleaver & derotation block 15010 isapplied to the fourth block 15300 for processing the PLS-pre/postinformation can be signaled through the above-described preamble.

The constellation demapper block 15020 can perform a reverse process ofthe process performed by the constellation mapper block 14010illustrated in FIG. 14. That is, the constellation demapper block 15020can demap cell-deinterleaved data without performing derotation.

The third block 15200 for MIMO can include a complex symbol parsingblock 15210 and a Q-block deinterleaver block 15220, as shown in FIG.15.

The complex symbol parsing block 15210 can perform a reverse process ofthe process performed by the complex symbol generator block 14220illustrated in FIG. 14. That is, the complex symbol parsing block 15210can parse complex data symbols and demap the same to bit data. In thiscase, the complex symbol parsing block 15210 can receive complex datasymbols through at least two paths.

The Q-block deinterleaver block 15220 can perform a reverse process ofthe process carried out by the Q-block interleaver block 14210illustrated in FIG. 14. That is, the Q-block deinterleaver block 15220can restore Q size blocks according to row-column deinterleaving,restore the order of permuted blocks to the original order and thenrestore positions of parity bits to original positions according toparity deinterleaving.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

As illustrated in FIG. 15, the demapping & decoding module according toanother embodiment of the present invention can output data pipes andPLS information processed for respective paths to the output processor.

As described above, the apparatus and method for transmitting broadcastsignals according to an embodiment of the present invention canmultiplex signals of different broadcast transmission/reception systemswithin the same RF channel and transmit the multiplexed signals and theapparatus and method for receiving broadcast signals according to anembodiment of the present invention can process the signals in responseto the broadcast signal transmission operation. Accordingly, it ispossible to provide a flexible broadcast transmission and receptionsystem.

FIG. 16 is a view illustrating a mode adaptation module according toanother embodiment of the present invention.

The above-described input formatting module may include a modeadaptation module as described above. The mode adaptation moduleaccording to the current embodiment of the present invention may beslightly different from the above-described mode adaptation module asillustrated in FIG. 16.

The mode adaptation module according to the current embodiment mayinclude a preprocessing block, input interface blocks, input streamsynchronizer blocks, compensating delay blocks, header compressionblocks, null data reuse blocks, null packet deletion blocks and/or BBframe header insertion blocks.

Here, the input interface blocks, the input stream synchronizer blocks,the compensating delay blocks and the null packet deletion blocks mayperform the same operations as those of the above-described modeadaptation module.

The preprocessing block may split or demultiplex multiple input streamsinto multiple data pipes. Here, the data pipes may also be calledPhysical Layer Pipes (PLPs). At this time, the input streams may be inthe form of TS (MPEG2-TS), IP (Internet protocol) and/or GS (Genericstream). Other types of input streams may also be used according toembodiments.

The header compression block may compress a packet header. This servesto increase the transmission efficiency of a TS or IP input stream.Since a receiver already has a priori information of the header, knowndata may be deleted by a transmitter. For example, information such as aPID may be compressed and other types of information may be deleted orreplaced. According to another embodiment, the header compression blockmay be located next to the null packet deletion block.

The null data reuse block may insert null data into a packet afterheader compression. This block may be omitted according to anembodiment.

The BB frame header insertion block according to the current embodimentmay operate differently from the above-described BB frame headerinsertion block. The present invention proposes a data field lengthsignaling reduction method of a Base Band (BB) frame. This method may beperformed by the BB frame header insertion block according to thecurrent embodiment. A BB frame and a BB frame header may be configuredusing the method proposed by the present invention. The presentinvention relates to a BB frame generation procedure for processing anddelivering an input stream to an FEC block. The method proposed by thepresent invention may be a method for increasing transmission efficiencyby reducing overhead of a BB frame header. A detailed description of theBB frame header insertion block will be given below.

In a related art, a BB frame allocates a data field length (DFL) toevery BB frame header to report the length of a data field to areceiver. This DFL may be 16 bits or 11 bits. As such, overhead is highin the related art.

In a BB frame having a fixed size, the length of a data field may differif the BB frame is not completely filled with data or if the BB frameincludes in-band signaling information.

In another related art, a BB frame transmits only an indicator insteadof directly reporting the length of a data field. Further, the BB framesignals the length of padding of the BB frame, in the padding. However,in this case, in-band signaling is not considered and thus restrictionsmay be caused when in-band signaling is used.

The method proposed by the present invention may be a BB frame headerconfiguration method for reducing DFL and inserting an additional field.Here, the additional field may indicate the type of in-band signaling orbe used for another purpose. Using the method proposed by the presentinvention, overhead may be minimized and various functions may be addedto padding (or stuffing).

FIG. 17 is a view illustrating an output processor according to anotherembodiment of the present invention.

The above-described output processor may include a BB frame headerparser block as described above. The output processor according to thecurrent embodiment of the present invention may be slightly differentfrom the above-described output processor as illustrated in FIG. 17.

The output processor according to the current embodiment of the presentinvention may include BB frame header parser blocks, null packetinsertion blocks, null data regenerator blocks, header de-compressionblocks, a TS clock regeneration block, de-jitter buffer blocks and/or aTS recombining block.

Here, the null packet insertion blocks, the TS clock regeneration block,the de-jitter buffer blocks and the TS recombining block may perform thesame operations as those of the above-described output processor.

The BB frame header configuration method proposed by the presentinvention may correspond to the BB frame header parser block at areceiver. The BB frame header parser block according to the currentembodiment may operate differently from the above-described BB frameheader parser block. The BB frame header parser block according to thecurrent embodiment may parse a header of a BB frame according to themethod proposed by the present invention. A detailed description of a BBframe and BB frame header configuration method proposed by the presentinvention will be given below.

The null data regenerator block may be a component corresponding to thenull data reuse block of a transmitter. The null data regenerator blockmay output an output thereof to the header de-compression block. Thisblock may be omitted according to an embodiment.

The header de-compression block may be a component corresponding to theheader compression block of a transmitter. The header de-compressionblock may de-compress a compressed packet header. As described above,the packet header may have been compressed to increase the transmissionefficiency of a TS or IP input stream. According to another embodiment,the header de-compression block may be located prior to the null packetinsertion block.

FIG. 18 is a view illustrating a BB frame generation procedure accordingto a related art.

An input data stream may be split to an appropriate length to beprocessable by FEC. A BB frame may be generated using the split datastream.

A value obtained by subtracting the length of a BB frame header from atotal length of the BB frame may correspond to the length of a datafield. Actual user packets (UPs) may be inserted into this data field.The length of the data field may be indicated by a DFL field of the BBframe header. The DFL field may also be called DFL.

Then, the BB frame may be encoded by a preset FEC block. The totallength of the BB frame may be fixed. The length of the data field maydiffer if the UPs are insufficient and thus do not completely fill theBB frame or if in-band signaling information is included intentionally.When the BB frame is not completely filled, the empty space may befilled with stuffing.

FIG. 19 is a view illustrating a BB frame generation procedure accordingto another related art.

In the other related art, when a frame is not completely filled withdata to be transmitted, stuffing bytes may also be inserted. STUFFI maybe inserted into a TP header to signal these stuffing bytes. The TPheader may be the same concept as a BB frame header.

If a BB frame is completely filled with UPs, no stuffing byte may exist.In this case, STUFFI may be set to 0.

If a BB frame is not completely filled with UPs, stuffing bytes mayexist. In this case, STUFFI may be set to 1.

The first byte of a payload of the frame is checked to detect the numberof inserted stuffing bytes. If the first byte has a value of 0xFF, thismay indicate 1 stuffing byte. If the first two bytes respectively havevalues of 0xFE and 0xFF, this may indicate 2 stuffing bytes. When thenumber of stuffing bytes is 3 or more, the length of stuffing bytes maybe signaled using the values of the first two bytes respectively as MSBsand LSBs.

In the table of FIG. 19, N may denote a total length of stuffing bytes.If N is 1 byte, the length of a field indicating the total length ofstuffing bytes may be 1 byte. This may have a value of 0xFF as describedabove. In this case, no more stuffing bytes follow 0xFF because N is 1byte.

If N is 2 bytes, the length of the field indicating the total length ofstuffing bytes may be 2 bytes. These may have values of 0xFE and 0xFF asdescribed above. No more stuffing bytes may follow 0xFE and 0xFF becauseN is 2 bytes.

If N is 3 or more bytes, i.e., if N has a value between 3 and 65278, thelength of the field indicating the total length of stuffing bytes mayalso be 2 bytes. As described above, these 2 bytes may be MSBs and LSBs.The total length of stuffing bytes may be signaled using these 2 bytes.Additional stuffing bytes may follow the MSBs and LSBs. Since the totallength of stuffing bytes is N and the length of the MSBs and LSBs is 2bytes, the length of following stuffing bytes may be N−2 bytes.

FIG. 20 is a view illustrating a BB frame generation procedure accordingto a still other related art.

In the still other related art, an indicator of 2 bits may be used toindicate the state of stuffing bytes. This indicator may be called PADI.

If stuffing bytes, i.e., padding, do not exist, PADI may be set to 00.In the first BB frame of FIG. 20, since the value of PADI is 00, nopadding exists.

If PADI is 01, this may indicate that padding is 1 byte. In the secondBB frame of FIG. 20, since the value of PADI is 01, 1 byte exists aspadding (P denotes a padding byte).

If PADI is 10, this may indicate that 2 or more padding bytes exist. Inthis case, a padding field may signal the length of padding using, forexample, MSBs and LSBs. In the third BB frame of FIG. 20, since thevalue of PADI is 10, the first two bytes of the padding field areallocated as MSBs and LSBs. A padding field marked as P may be locatednext to the MSBs and LSBs.

If PADI is 11, this may indicate a reserved state.

FIG. 21 is a view illustrating a BB frame configuration method accordingto an embodiment of the present invention.

The present invention proposes the following method to configure a BBframe and a BB frame header.

Initially, a BB frame may include a BB frame header, a stuffing fieldand/or a payload. According to an embodiment, the stuffing field and thepayload may also be called a BB frame payload.

The BB frame header may describe the format of the payload, i.e., datafield. Information such as DNP or ISSY related information may beadditionally inserted prior to the stuffing field. The payload may referto a data field.

The BB frame header may include a STUFFI field. The STUFFI field mayfunction as a stuffing indicator. The STUFFI field may be 1 bit. STUFFImay describe whether a stuffing field exists in the BB frame. Thelocation of STUFFI may vary according to embodiments.

If the value of STUFFI is 0, the BB frame may include no stuffing fieldand no in-band signaling field. That is, in this case, the entirepayload may be used to transmit UPs.

If the value of STUFFI is 1, the BB frame may include a stuffing fieldor an in-band signaling field. That is, in this case, an information,padding or in-band field other than UPs may exist in the payload.

According to an embodiment of the present invention, the meanings of 0and 1 as the values of STUFFI may be switched.

The stuffing field may include a stuffing field header and/or a stuffingdata region. Here, the stuffing data region may include stuffing dataand/or in-band signaling information.

The stuffing field header may be 2 bytes according to an embodiment. Thestuffing field header may include PAD_ONE, PAD_TYPE and/or PAD_LEN.

Here, the first byte of FIG. 21 may refer to the first byte of thestuffing field. The second byte of FIG. 21 may also belong to thestuffing field. According to an embodiment, the first two bytes maycorrespond to the stuffing field header. According to an embodiment,bytes from the third byte may be included in the stuffing data region orthe payload.

PAD_ONE may be called STUFF_ONE according to another embodiment. IfSTUFFI is 1, this may indicate STUFF_ONE. STUFF_ONE may indicate whetherthe length of stuffing bytes is 1 byte or not. STUFF_ONE may be an MSBof 1 bit. If STUFF_ONE is 1, the length of stuffing bytes may be 1 byte.In this case, STUFF_LEN_LSB indicating the length of stuffing bytes maynot be used. Further, all STUFF_LEN_MSBs may be set to 0. In this case,according to another embodiment, all STUFF_LEN_MSBs may be set to 1.That is, according to an embodiment, 1 stuffing byte may have a value of00000000, 11111111, 10000000 or 01111111.

If STUFF_ONE is 0, the length of stuffing bytes may be greater than 1byte. In this case, the stuffing field header of 2 bytes may be used toindicate the length and type of the stuffing data region.

The meanings of the values of STUFF_ONE may be switched according to adesigner. That is, the meanings of 1 and 0 may be switched.

STUFF_ONE (PAD_ONE) of FIG. 21 may be located at the first bit of thefirst byte. This location is variable according to embodiments.STUFF_ONE may be located in the BB frame header according to anotherembodiment.

According to another embodiment, a single 2-bit field functioning asSTUFFI and STUFF_ONE may be configured. Since each of STUFFI andSTUFF_ONE has 1 bit, a single 2-bit field may be configured as asubstitute therefor. This field may be located in the BB frame header orthe stuffing field.

PAD_LEN may be called STUFF_LEN according to another embodiment.STUFF_LEN may be divided into STUFF_LEN_MSB and/or STUFF_LEN_LSB.STUFF_LEN_MSB and STUFF_LEN_LSB may be a field of 5 bits and a field of8 bits, respectively. These two fields may be used to indicate a totallength of the stuffing field. According to another embodiment, thelengths of STUFF_LEN_MSB and STUFF_LEN_LSB may be switched, e.g., 8 bitsand 5 bits. Further, according to another embodiment, the locations ofthe two may also be switched. According to an embodiment, a fieldindicating the length of padding may be located in the stuffing dataregion.

In a conventional case, the length of padding is indicated using thefirst 2 bytes. However, if 64K LDPC is used, the length of padding is upto 6370 bytes (64 k, ⅚ code rate, BCH code). Thus, the length of paddingmay be sufficiently indicated using 13 bits (2̂13=8192 bytes).Accordingly, PAD_LEN may be 13 (5+8) bits in the present invention.

If the length of padding is indicated using 13 bits as described above,the first 2 bytes may have 2 extra bits. In the present invention, thesetwo extra bits are allocated as PAD_TYPE to signal the type of a paddingregion if the padding region is used for another purpose (e.g., in-bandsignaling).

PAD_TYPE may be called STUFF_TYPE according to another embodiment.STUFF_TYPE is a field of 2 bits as described above and may indicate thetype of the stuffing data (or stuffing data region). In the case of 00,the stuffing data region may include the stuffing data only. In the caseof 01, specific-type in-band signaling information may be includedtogether with the stuffing data in the stuffing data region. In the caseof 10, another-type in-band signaling information may be includedtogether with the stuffing data in the stuffing data region. In the caseof 11, both the specific-type in-band signaling information and theother-type in-band signaling information may be included together withthe stuffing data in the stuffing data region.

Here, the specific-type in-band signaling information may refer toin-band A and the other-type in-band signaling information may refer toin-band B. However, this is merely exemplary and the types indicated bythe values of STUFF_TYPE may be changed. Further, STUFF_TYPE mayindicate the configuration of the BB frame or the payload. For example,STUFF_TYPE may indicate the first full packet of the payload, which isnot cut.

If the stuffing field is signaled as described above according to thepresent invention, in-band signaling may be inserted into a plurality ofother frames. Further, distinction from padding only with no in-bandsignaling is possible.

STUFF_TYPE may be located in the BB frame header according to anembodiment. Alternatively, STUFF_TYPE may be located in the stuffingfield as in the current embodiment. The length of STUFF_TYPE may bechanged according to embodiments.

The meanings of the values of STUFF_TYPE may be switched according to adesigner. For example, the meaning of 00 and the meaning of 11 may beswitched. Further, the meaning of 10 and the meaning of 01 may beswitched.

The stuffing data may be all 0s or all 1s.

FIG. 21 illustrates Case #1 to Case #6 of the BB frame configurationmethod proposed by the present invention. A description is now given ofeach case.

Case #1 may be a case in which only data exists and stuffing data andin-band signaling do not exist in the BB frame. In this case, STUFFI mayhave a value of 0. Accordingly, the BB frame may not have a stuffingfield and a data region, i.e., payload, may be located immediately nextto the BB frame header.

Case #2 may be a case in which a stuffing field of 1 byte exists andin-band signaling does not exist in the BB frame. In this case, STUFFImay have a value of 1 because the stuffing field exists in the BB frame.This stuffing field may have a size of 1 byte. The first bit of thestuffing field is a STUFF_ONE field and has a value of 1 because thesize of the stuffing field is 1 byte. The remaining 7 bits of thestuffing field may have a value of 0000000 as described above. In thiscase, the value of the whole stuffing field may be 10000000. FIG. 21illustrates that the remaining 7 bits have a value of 1111111 accordingto another embodiment. That is, in this case, the value of the wholestuffing field may be 11111111. A data region, i.e., payload, may belocated next to the stuffing field.

Case #3 may be a case in which a stuffing field having a size greaterthan 1 byte exists and in-band signaling does not exist in the BB frame.Here, the stuffing field may be 2 or more bytes. In this case, STUFFImay have a value of 1 because the stuffing field exists. The stuffingfield may have a stuffing field header of 2 bytes. The first bit of thefirst byte of the stuffing field header is a STUFF_ONE field and mayhave a value of 0 because the size of the stuffing field is greater than1 byte. The second and third bits of the first byte of the stuffingfield header may be the above-described STUFF_TYPE field. Since onlystuffing data exists in the stuffing data region of the BB frame,STUFF_TYPE may have a value of 00 as described above. FIG. 21illustrates that STUFF_TYPE has a value of 11 according to anotherembodiment. That is, in this case, the value 11 of the STUFF_TYPE fieldmay indicate that only stuffing data exists in the stuffing data regionof the BB frame. STUFF_LEN_MSB and STUFF_LEN_LSB of the stuffing fieldheader next to STUFF_TYPE may have length information of the stuffingfield. The length of the stuffing field may be indicated using a totalof 13 bits as described above. The stuffing data region may be locatednext to STUFF_LEN_MSB and STUFF_LEN_LSB. In this case, the stuffing dataregion may include the stuffing data only.

Case #4 may be a case in which a stuffing field having a size greaterthan 1 byte exists and in-band A signaling also exists in the BB frame.Here, stuffing data and the in-band A signaling may exist in thestuffing data region of the BB frame. The in-band A signaling may referto the above-described specific-type in-band signaling. In this case,STUFFI may have a value of 1 because the stuffing field exists. Thefirst bit of the first byte of the stuffing field header is a STUFF_ONEfield and may have a value of 0 because the size of the stuffing fieldis greater than 1 byte. The second and third bits of the first byte ofthe stuffing field header may be the above-described STUFF_TYPE field.Since the in-band A signaling exists in the stuffing data region of theBB frame, STUFF_TYPE may have a value of 10 as described above. Thisvalue may be 01 according to another embodiment. STUFF_LEN_MSB andSTUFF_LEN_LSB of the stuffing field header next to STUFF_TYPE may havelength information of the stuffing field. The length of the stuffingfield may be indicated using a total of 13 bits as described above. Thestuffing data region may be located next to STUFF_LEN_MSB andSTUFF_LEN_LSB. In this case, the stuffing data region may include thein-band A signaling in addition to the stuffing data.

Case #5 may be a case in which a stuffing field having a size greaterthan 1 byte exists and in-band B signaling also exists in the BB frame.Here, stuffing data and the in-band B signaling may exist in thestuffing data region of the BB frame. The in-band B signaling may referto the above-described other-type in-band signaling. In this case,STUFFI may have a value of 1 because the stuffing field exists. Thefirst bit of the first byte of the stuffing field header is a STUFF_ONEfield and may have a value of 0 because the size of the stuffing fieldis greater than 1 byte. The second and third bits of the first byte ofthe stuffing field header may be the above-described STUFF_TYPE field.Since the in-band B signaling exists in the stuffing data region of theBB frame, STUFF_TYPE may have a value of 01 as described above. Thisvalue may be 10 according to another embodiment. STUFF_LEN_MSB andSTUFF_LEN_LSB of the stuffing field header next to STUFF_TYPE may havelength information of the stuffing field. The length of the stuffingfield may be indicated using a total of 13 bits as described above. Thestuffing data region may be located next to STUFF_LEN_MSB andSTUFF_LEN_LSB. In this case, the stuffing data region may include thein-band B signaling in addition to the stuffing data.

Case #6 may be a case in which a stuffing field having a size greaterthan 1 byte exists and in-band A signaling and in-band B signaling alsoexist in the BB frame. Here, stuffing data and both the in-band Asignaling and the in-band B signaling may exist in the stuffing dataregion of the BB frame. In this case, STUFFI may have a value of 1. Thefirst bit of the first byte of the stuffing field header is a STUFF_ONEfield and may have a value of 0 because the size of the stuffing fieldis greater than 1 byte. The second and third bits of the first byte ofthe stuffing field header may be the above-described STUFF_TYPE field.Since the in-band A signaling and the in-band B signaling exist in thestuffing data region of the BB frame, STUFF_TYPE may have a value of 11as described above. FIG. 21 illustrates that STUFF_TYPE has a value of00 according to another embodiment. That is, in this case, the value 00of the STUFF_TYPE field may indicate that in-band A signaling andin-band B signaling exist in the stuffing data region. STUFF_LEN_MSB andSTUFF_LEN_LSB of the stuffing field header next to STUFF_TYPE may havelength information of the stuffing field. The length of the stuffingfield may be indicated using a total of 13 bits as described above. Thestuffing data region may be located next to STUFF_LEN_MSB andSTUFF_LEN_LSB. In this case, the stuffing data region may include thein-band A signaling and the in-band B signaling in addition to thestuffing data.

FIG. 22 is a view illustrating BB frames configured using the BB frameconfiguration method according to an embodiment of the presentinvention.

FIG. 22( a) may correspond to a case in which a BB frame includes dataonly with no padding, i.e., stuffing data. STUFFI of a BB frame headermay have a value of 0. A payload is located immediately next to the BBframe header without locating a stuffing field therebetween. This maycorrespond to the above-described Case #1.

FIG. 22( b) may correspond to a case in which a BB frame includes 1 byteof padding. In this case, STUFFI of a BB frame header may have a valueof 1. The first bit of the first byte thereof is STUFF_ONE and may havea value of 1. This may indicate that padding is 1 byte. In FIG. 22( b),the padding may have a value of 11111111 (0xFF). As described above, thepadding may have a value of 10000000 according to another embodiment.This may correspond to the above-described Case #2.

FIG. 22( c) may correspond to a case in which a BB frame includes 2bytes of padding. In this case, STUFFI of a BB frame header may have avalue of 1. Here, STUFF_ONE may have a value of 0. STUFF_TYPE mayindicate that in-band signaling is not used and only stuffing data isused. That is, according to an embodiment, STUFF_TYPE may have a valueof 00. The remaining 13 bits may indicate that the length of a stuffingfield is 2 bytes. These 13 bits may be STUFF_LEN_MSB and STUFF_LEN_LSB.According to another embodiment, STUFF_LEN_MSB and STUFF_LEN_LSB may notbe used and the stuffing data may be located immediately next toSTUFF_TYPE. This may correspond to the above-described Case #3 and, moreparticularly, a case in which the stuffing field is 2 bytes.

FIG. 22( d) may correspond to a case in which a BB frame includes nbytes of padding. In this case, STUFFI of a BB frame header may have avalue of 1. Here, STUFF_ONE may have a value of 0. STUFF_TYPE mayindicate that in-band signaling is not used and only stuffing data isused. That is, according to an embodiment, STUFF_TYPE may have a valueof 00. The remaining 13 bits may indicate that the length of a stuffingfield is n bytes. These 13 bits may be STUFF_LEN_MSB and STUFF_LEN_LSB.The stuffing data may be located next to STUFF_LEN_MSB andSTUFF_LEN_LSB. This may correspond to the above-described Case #3 and,more particularly, a case in which the stuffing field is 3 or morebytes.

FIG. 22( e) may correspond to a case in which a BB frame includes nbytes of padding with in-band A signaling. In this case, STUFFI of a BBframe header may have a value of 1. Here, STUFF_ONE may have a value of0. STUFF_TYPE may indicate that the in-band A signaling is used. Thatis, according to an embodiment, STUFF_TYPE may have a value of 01. Thevalue itself of STUFF_TYPE may be changed as described above. Theremaining 13 bits may indicate that the length of a stuffing field is nbytes. These 13 bits may be STUFF_LEN_MSB and STUFF_LEN_LSB. The in-bandA signaling data may be located next to STUFF_LEN_MSB and STUFF_LEN_LSB.This may correspond to the above-described Case #4.

FIG. 22( f) may correspond to a case in which a BB frame includes nbytes of padding with in-band B signaling. In this case, STUFFI of a BBframe header may have a value of 1. Here, STUFF_ONE may have a value of0. STUFF_TYPE may indicate that the in-band B signaling is used. Thatis, according to an embodiment, STUFF_TYPE may have a value of 10. Thevalue itself of STUFF_TYPE may be changed as described above. Theremaining 13 bits may indicate that the length of a stuffing field is nbytes. These 13 bits may be STUFF_LEN_MSB and STUFF_LEN_LSB. The in-bandB signaling data may be located next to STUFF_LEN_MSB and STUFF_LEN_LSB.This may correspond to the above-described Case #5.

FIG. 22( g) may correspond to a case in which a BB frame includes nbytes of padding with in-band A signaling and in-band B signaling. Inthis case, STUFFI of a BB frame header may have a value of 1. Here,STUFF_ONE may have a value of 0. STUFF_TYPE may indicate that both thein-band A signaling and the in-band B signaling are used. That is,according to an embodiment, STUFF_TYPE may have a value of 11. The valueitself of STUFF_TYPE may be changed as described above. The remaining 13bits may indicate that the length of a stuffing field is n bytes. These13 bits may be STUFF_LEN_MSB and STUFF_LEN_LSB. The in-band A signalingdata and the in-band B signaling data may be located next toSTUFF_LEN_MSB and STUFF_LEN_LSB. This may correspond to theabove-described Case #6.

FIG. 23 is a view illustrating a result of comparing overheads ofvarious BB frame configuration methods.

A line marked DVB-T2 shows overhead of the above-described related art.DVB-T2 may refer to the terrestrial television broadcasting systemstandards of Digital Video Broadcasting (DVB). DVB-T2 may also refer tothe next-generation terrestrial broadcasting standards of Europe. Assuch, the line marked DVB-T2 shows overhead of a BB frame configuredaccording to the above technical standards.

A line marked MH shows overhead of the above-described other relatedart. MH may refer to the Mobile/Handheld DTV system standards of theConsumer Electronics Association (CEA). As such, the line marked MHshows overhead of a BB frame configured according to the above technicalstandards.

A line marked SS&SN shows overhead of the above-described still otherrelated art. SS&SN may refer to one of related arts. Overhead of a BBframe and a BB frame header configured according to a method of thisrelated art is shown as the line marked SS&SN.

Table 1 shows a result of comparing overheads of various BB frameconfiguration methods.

TABLE 1 FEC 64k 16k CR ⅚ ⅘ ¾ ⅔ ⅗ ½ ⅚ ⅘ ¾ ⅔ ⅗ ½ kBCH 53840 51648 4840843040 38688 32208 13152 12600 11880 10800 9720 7200 DVB-T2 0.0297 0.03100.0331 0.0372 0.0414 0.0497 0.1217 0.1270 0.1347 0.1481 0.1646 0.2222 MH0.0019 0.0019 0.0021 0.0023 0.0026 0.0031 0.0076 0.0079 0.0084 0.00930.0103 0.0139 SS&SN 0.0037 0.0039 0.0041 0.0046 0.0052 0.0062 0.01520.0159 0.0168 0.0185 0.0206 0.0278 LG 0.0019 0.0019 0.0021 0.0023 0.00260.0031 0.0076 0.0079 0.0084 0.0093 0.0103 0.0139

The overhead may refer to overhead of a field indicating the length of adata field.

The related art uses a 2-byte field in every BB frame and thus may haveoverhead up to 0.22%.

The other related art uses only a 1-bit field and thus may have overheadup to 0.0139%. This value may be the lowest value.

The still other related art may use a 2-bit field. In this case,overhead may be doubled compared to the other related art.

A line marked LG shows overhead according to the present invention. Inthe present invention, only a 1-bit field may be used for signaling of astuffing field. Accordingly, overhead may be minimized. Further, anextra 2-bit field may be additionally prepared and used to indicate thetype of in-band signaling. The present invention may use this extrafield for another purpose, e.g., to indicate the configuration of a BBframe.

FIG. 24 illustreates a method of transmitting broadcast signal accordingto an embodiment of the present invention.

The method includes processing input streams, encoding data of the PLPs(Physical Layer Pipes)s, building at least one signal frame, and/ormodulating data by OFDM method & transmitting broadcast signals.

In step of processing input streams, the above described inputformatting module may process input streams. The input formatting modulecan process input streams into BB (Base Band) frames in PLPs. The PLPcan be divided into BB frames. The input formatting module candemultiplex input streams into PLPs.

In step of encoding data of the PLPs, the above described coding &modulation module may encode data of the PLPs. The PLP can be alsoreferred to as DP. This step can include LDPC (Low Density Parity Check)encoding, bit interleaving, mapping onto constellations, MIMO (MultiInput Multi Output) encoding, and/or time interleaving. The data in eachdata path can be encoded based on a code rate.

In step of building at least one signal frame, the above-described framestructure module can build signal frames by mapping the encoded data ofthe PLPs.

In step of modulating data by OFDM method & transmitting broadcastsignals, the above-described waveform generation module can modulatedata in OFDM method, and transmit the broadcast signals.

In this embodiment, at least one of the BB frames may include a stuffingfield and a first indicator describing whether the stuffing field isincluded in the BB frame. The stuffing field is described above. Thefirst indicator may refer to STUFFI field described above. The firstindicator may refer to some other fields in the BB frame depends onembodiments.

In a method of transmitting broadcast signals according to otherembodiment of the present invention, the step of processing inputstreams further includes, generating data fields of the BB frames byusing the input streams, and inserting BB frame headers to the BBframes. This process may be conducted by the input formatting module. Bygenerating data fields and inserting BB frame headers, the BB frame canbe generated by using the input streams.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, the BB frame further includes asecond indicator indicating length of the stuffing field. The secondindicator may refer to STUFF_LEN_MSB and/or STUFF_LEN_LSB. These fieldsmay indicates the length of the stuffing field. The second indicator mayrefer to some other fields in the BB frame depends on embodiments.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, the BB frame further includes athird indicator having information about composition of the BB frame.The third indicator may refer to STUFF_TYPE field. The third indicatormay refer to some other fields in the BB frame depends on embodiments.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, the information in the thirdindicator indicates a type of stuffing data in the stuffing field. Thethird indicator may refer to STUFF_TYPE field. The third indicator mayrefer to some other fields in the BB frame depends on embodiments. Theinformation in the STUFF_TYPE field is described above.

In a method of transmitting broadcast signals according to anotherembodiment of the present invention, the step of the encoding data ofthe PLPs further includes, encoding the BB frames in the PLPs with LDPC(Low Density Parity Check) codes, bit interleaving the LDPC encoded datain the PLPs, mapping the bit interleaved data onto constellations, MIMO(Multi Input Multi Output) encoding the mapped data, and/or timeinterleaving the MIMO encoded data.

The encoding with LDPC codes may correspond to LDPC encoding by LDPCencoder. The LDPC encoder may encode BB frames in the PLPs with LDPCcodes. Bit interleaving may correspond to bit interleaving by bitinterleaver. Constellation mapping may correspond to the constellationmapping conducted by constellation mapper. MIMO encoding can refer toMIMO encoding performed by above described MIMO encoder. Timeinterleaving can correspond to time interleaving by time interleaver.

The above-described steps can be omitted or replaced by steps executingsimilar or identical functions according to design.

FIG. 25 illustrates a method of receiving broadcast signal according toan embodiment of the present invention.

The method includes receiving broadcast signals & demodulating data byOFDM method, parsing the at least one signal frame, decoding the data ofthe PLPs, and/or processing BB frames.

In step of receiving broadcast signals & demodulating data by OFDMmethod, the above-described synchronization & demodulation modulereceives broadcast signals, and demodulates data by OFDM method.

In step of parsing the at least one signal frame, the above-describedframe parsing module parses the signal frame by demapping data of thePLPs.

In step of decoding the data of the PLPs, the above-described demapping& decoding module decodes the PLP data. Step of decoding the PLP datacan include time deinterleaving, MIMO (Multi Input Multi Output)decoding, and so on.

In step of processing BB frames, the above described output processormay conduct output processing on the BB fraems in the PLPs. The outputprocessor may output streams.

In this embodiment, at least one of the BB frames may include a stuffingfield and a first indicator describing whether the stuffing field isincluded in the BB frame. The stuffing field is described above. Thefirst indicator may refer to STUFFI field described above. The firstindicator may refer to some other fields in the BB frame depends onembodiments.

In a method of receiving broadcast signals according to other embodimentof the present invention, the step of the processing BB fraems in thePLPs further includes, removing BB frame headers from the BB frames,and/or generating output streams by using data fields of the BB frames.By removing BB frame headers and generating output streams from the BBframes, output streams can be outputted.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, the BB frame further includes asecond indicator indicating length of the stuffing field. The secondindicator may refer to STUFF_LEN_MSB and/or STUFF_LEN_LSB. These fieldsmay indicates the length of the stuffing field. The second indicator mayrefer to some other fields in the BB frame depends on embodiments.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, the BB frame further includes athird indicator having information about composition of the BB frame.The third indicator may refer to STUFF_TYPE field. The third indicatormay refer to some other fields in the BB frame depends on embodiments.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, the information in the thirdindicator indicates a type of stuffing data in the stuffing field. Thethird indicator may refer to STUFF_TYPE field. The third indicator mayrefer to some other fields in the BB frame depends on embodiments. Theinformation in the STUFF_TYPE field is described above.

In a method of receiving broadcast signals according to anotherembodiment of the present invention, the decoding the data of the PLPsfurther includes, time deinterleaving the data of the PLPs, MIMO (MultiInput Multi Output) decoding the time deinterleaved data of the PLPs,demapping the MIMO decoded data from constellations, bit deinterleavingthe demapped data, and/or processing the bit deinterleaved data withLDPC (Low Density Parity Check) codes to output BB frames.

In step of time deinterleaving, the above-described time deinterleavercan conduct time deinterleaving PLP data. In step of MIMO decoding, theabove-described MIMO decoder can conduct MIMO decoding PLP data. MIMOdecoding can be conducted by using MIMO matrix including MIMOcoefficient. MIMO coefficient can be used for adjusting power imbalance.In step of demapping from constellations, the above-describedconstellation demapper can conduct demapping. The demapping can beconducted on PLP data. In step of bit deinterleaving, theabove-described bit deinterleaver can conduct bit deinterleaving. Instep of LDPC decoding. the above-described LDPC decoder (or FEC decoder)can decode PLP data according to LDPC code, to output BB frames.

The above-described steps can be omitted or replaced by steps executingsimilar or identical functions according to design.

Although the description of the present invention is explained withreference to each of the accompanying drawings for clarity, it ispossible to design new embodiment(s) by merging the embodiments shown inthe accompanying drawings with each other. And, if a recording mediumreadable by a computer, in which programs for executing the embodimentsmentioned in the foregoing description are recorded, is designed innecessity of those skilled in the art, it may belong to the scope of theappended claims and their equivalents.

An apparatus and method according to the present invention may benon-limited by the configurations and methods of the embodimentsmentioned in the foregoing description. And, the embodiments mentionedin the foregoing description can be configured in a manner of beingselectively combined with one another entirely or in part to enablevarious modifications.

In addition, a method according to the present invention can beimplemented with processor-readable codes in a processor-readablerecording medium provided to a network device. The processor-readablemedium may include all kinds of recording devices capable of storingdata readable by a processor. The processor-readable medium may includeone of ROM, RAM, CD-ROM, magnetic tapes, floppy discs, optical datastorage devices, and the like for example and also include such acarrier-wave type implementation as a transmission via Internet.Furthermore, as the processor-readable recording medium is distributedto a computer system connected via network, processor-readable codes canbe saved and executed according to a distributive system.

It will be appreciated by those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both apparatus and method inventions are mentioned in this specificationand descriptions of both of the apparatus and method inventions may becomplementarily applicable to each other.

Various embodiments have been described in the best mode for carryingout the invention.

The present invention has industrial applicability in broadcasting andcommunication field.

What is claimed is:
 1. A method of transmitting broadcast signals, themethod including: processing input streams into BB (Base Band) frames inPLPs (Physical Layer Pipes); encoding data of the PLPs; building atleast one signal frame by mapping the encoded data of the PLPs; andmodulating data in the built signal frame by OFDM (Orthogonal FrequencyDivision Multiplexing) method and transmitting the broadcast signalshaving the modulated data, wherein at least one of the BB framesincludes a stuffing field and a first indicator describing whether thestuffing field is included in the BB frame.
 2. The method of claim 1,wherein the processing input streams further includes, generating datafields of the BB frames by using the input streams, and inserting BBframe headers to the BB frames.
 3. The method of claim 1, wherein the BBframe further includes a second indicator indicating length of thestuffing field.
 4. The method of claim 1, wherein the BB frame furtherincludes a third indicator having information about composition of theBB frame.
 5. The method of claim 4, wherein the information in the thirdindicator indicates a type of stuffing data in the stuffing field. 6.The method of claim 1, wherein the encoding data of the PLPs furtherincludes, encoding the BB frames in the PLPs with LDPC (Low DensityParity Check) codes, bit interleaving the LDPC encoded data in the PLPs,mapping the bit interleaved data onto constellations, MIMO (Multi InputMulti Output) encoding the mapped data, and time interleaving the MIMOencoded data.
 7. A method of receiving broadcast signals, the methodincluding: receiving the broadcast signals having at least one signalframe and demodulating data in the at least one signal frame by OFDM(Orthogonal Frequency Division Multiplexing) method; parsing the atleast one signal frame by demapping data of PLPs (Physical Layer Pipes);decoding the data of the PLPs; and processing BB (Base Band) frames inthe PLPs to output streams, wherein at least one of the BB framesincludes a stuffing field and a first indicator describing whether thestuffing field is included in the BB frame.
 8. The method of claim 7,wherein the processing BB frames in the PLPs further includes, removingBB frame headers from the BB frames, and generating output streams byusing data fields of the BB frames.
 9. The method of claim 7, whereinthe BB frame further includes a second indicator indicating length ofthe stuffing field.
 10. The method of claim 7, wherein the BB framefurther includes a third indicator having information about compositionof the BB frame.
 11. The method of claim 10, wherein the information inthe third indicator indicates a type of stuffing data in the stuffingfield.
 12. The method of claim 7, wherein the decoding the data of thePLPs further includes, time deinterleaving the data of the PLPs, MIMO(Multi Input Multi Output) decoding the time deinterleaved data of thePLPs, demapping the MIMO decoded data from constellations, bitdeinterleaving the demapped data, and processing the bit deinterleaveddata with LDPC (Low Density Parity Check) codes to output BB frames. 13.An apparatus for transmitting broadcast signals, the apparatusincluding: an input processing module for processing input streams intoBB (Base Band) frames in PLPs (Physical Layer Pipes); an encoding modulefor encoding data of the PLPs; a frame building module for building atleast one signal frame by mapping the encoded data of the PLPs; and amodulating module for modulating data in the built signal frame by OFDM(Orthogonal Frequency Division Multiplexing) method and transmitting thebroadcast signals having the modulated data, wherein at least one of theBB frames includes a stuffing field and a first indicator describingwhether the stuffing field is included in the BB frame.
 14. Theapparatus of claim 13, wherein the input processing module furtherincludes, a generating block for generating data fields of the BB framesby using the input streams, and a inserting block for inserting BB frameheaders to the BB frames.
 15. The apparatus of claim 13, wherein the BBframe further includes a second indicator indicating length of thestuffing field.
 16. The apparatus of claim 13, wherein the BB framefurther includes a third indicator having information about compositionof the BB frame.
 17. The apparatus of claim 16, wherein the informationin the third indicator indicates a type of stuffing data in the stuffingfield.
 18. The apparatus of claim 13, wherein the encoding modulefurther includes, a LDPC block for encoding the BB frames in the PLPswith LDPC (Low Density Parity Check) codes, a bit interleaving block forbit interleaving the LDPC encoded data in the PLPs, a constellationmapping block for mapping the bit interleaved data onto constellations,a MIMO (Multi Input Multi Output) block for MIMO encoding the mappeddata, and a time interleaving block for time interleaving the MIMOencoded data.
 19. An apparatus for receiving broadcast signals, theapparatus including: a demodulating module for receiving the broadcastsignals having at least one signal frame and demodulating data in the atleast one signal frame by OFDM (Orthogonal Frequency DivisionMultiplexing) method; a frame parsing module for parsing the at leastone signal frame by demapping data of PLPs (Physical Layer Pipes); adecoding module for decoding the data of the PLPs; and a outputprocessing module for processing BB (Base Band) frames in the PLPs tooutput streams, wherein at least one of the BB frames includes astuffing field and a first indicator describing whether the stuffingfield is included in the BB frame.
 20. The apparatus of claim 19,wherein the output processing module further includes, a removing blockfor removing BB frame headers from the BB frames, and a generating blockfor generating output streams by using data fields of the BB frames. 21.The apparatus of claim 19, wherein the BB frame further includes asecond indicator indicating length of the stuffing field.
 22. Theapparatus of claim 19, wherein the BB frame further includes a thirdindicator having information about composition of the BB frame.
 23. Theapparatus of claim 22, wherein the information in the third indicatorindicates a type of stuffing data in the stuffing field.
 24. Theapparatus of claim 19, wherein the decoding module further includes, atime deinterleaving block for time deinterleaving the data of the PLPs,a MIMO (Multi Input Multi Output) decoding block for MIMO decoding thetime deinterleaved data of the PLPs, a constellation demapping block fordemapping the MIMO decoded data from constellations, a bitdeinterleaving block for bit deinterleaving the demapped data, and aLDPC decoding block for processing the bit deinterleaved data with LDPC(Low Density Parity Check) codes to output BB frames.